How to Read Your Water Utility's Annual Report

Your Water Utility Publishes a Report Card Every Year

Every public water system in the United States serving more than 15 connections is required by law to publish an annual Consumer Confidence Report (CCR). This document tells you exactly what is in your drinking water, how it compares to legal limits, and where your water comes from. It is essentially a report card for your tap water.

The problem is that most CCRs are dense, technical documents filled with abbreviations, units of measurement, and tables that require a chemistry degree to interpret. This guide translates the jargon into plain language so you can actually use this free, valuable resource to understand your water quality.

Step 1: Find Your Report

Your water utility must make the CCR available to all customers by July 1 each year. Here is how to get it:

Online: Search "[your city name] water quality report" or "[your utility name] Consumer Confidence Report." Most utilities post current and past years' reports on their websites.

By mail: Many utilities mail an abbreviated version or a postcard with a link to the full report. Check your mail around June or July.

By request: You can call your water utility and request a copy at any time.

Through our site: Search your city on our [state pages](/all-states) for summarized water quality data drawn from public reporting.

If you are on a private well, your water is not covered by this reporting requirement. You are responsible for testing your own water. See our [well water testing guide](/blog/private-well-water-testing-guide) for recommendations.

Step 2: Understand the Source Water Section

The first section of most CCRs describes where your water comes from. This matters because source water type influences which contaminants are most likely to be present.

Surface Water

Lakes, rivers, and reservoirs are classified as surface water. Surface water sources are more susceptible to contamination from agricultural runoff, industrial discharge, and stormwater. They typically require more extensive treatment than groundwater.

Groundwater

Wells that tap into underground aquifers provide groundwater. Groundwater is naturally filtered by soil and rock layers and often requires less treatment than surface water. However, it can be affected by naturally occurring minerals (like arsenic or radon) and contamination that seeps into the aquifer from the surface.

Blended Sources

Many utilities use a combination of surface water and groundwater, blending them before distribution. The CCR should specify the percentage from each source.

Understanding your source helps you anticipate potential issues. For example, agricultural areas with surface water sources are more likely to have nitrate and pesticide concerns. Regions with naturally occurring arsenic in geological formations may see elevated arsenic in groundwater sources.

Step 3: Decode the Contaminant Table

The heart of the CCR is a table listing detected contaminants and their levels. This table typically includes several columns that can be confusing if you do not know what they mean.

Key Terms Decoded

MCL (Maximum Contaminant Level): The highest level of a contaminant that is legally allowed in drinking water. MCLs are set by the EPA and are enforceable. If your water exceeds an MCL, your utility must take corrective action and notify customers.

MCLG (Maximum Contaminant Level Goal): The level of a contaminant below which there is no known or expected health risk. MCLGs are aspirational, not enforceable. For carcinogens, the MCLG is often set at zero, which is technically unachievable but represents the ideal.

Level Detected (or Amount Detected): The actual concentration of the contaminant found in your water. This is the most important number in the table. Compare it to the MCL to assess whether your water is within legal limits.

Range: If your utility tests at multiple locations, this shows the lowest and highest levels detected. A wide range may indicate that water quality varies depending on where in the distribution system you live.

Violation (Yes/No): Whether the detected level exceeds the MCL. A "no" means compliance; a "yes" means your utility has exceeded the legal limit and must take action.

Likely Source: A brief description of where the contaminant typically comes from, such as "erosion of natural deposits" or "discharge from industrial facilities."

Units of Measurement

Water quality uses extremely small measurement units that can be disorienting:

ppm (parts per million) = milligrams per liter (mg/L). Think of one drop in a bathtub.

ppb (parts per billion) = micrograms per liter (ug/L). One thousand times smaller than ppm. Think of one drop in a swimming pool.

ppt (parts per trillion) = nanograms per liter (ng/L). One million times smaller than ppm. Used for PFAS measurements.

pCi/L (picocuries per liter): Used for radioactive contaminants like radium and radon.

NTU (Nephelometric Turbidity Units): Measures water cloudiness. Lower is better.

Step 4: Know Which Numbers to Focus On

You do not need to understand every line in the table. Focus on these key contaminants first:

Priority 1: Lead and Copper

These are regulated differently from other contaminants. Instead of testing the water leaving the treatment plant, utilities test at customer taps because lead and copper typically enter water from household plumbing, not from the source.

The CCR reports the "90th percentile" level, meaning 90% of samples tested at or below this level. The EPA Action Level for lead is 15 ppb. For copper, it is 1.3 ppm.

What to watch for: If the 90th percentile lead level is above 10 ppb, even if it is below the 15 ppb action level, consider testing your own tap and potentially installing a certified lead filter. Compare your area to others on our [lead contamination guide](/blog/lead-in-drinking-water-risks-solutions).

Priority 2: Disinfection Byproducts

Total Trihalomethanes (TTHMs): MCL is 80 ppb. These form when chlorine reacts with organic matter in the water.

Haloacetic Acids (HAA5): MCL is 60 ppb. Same formation mechanism as THMs.

Both are associated with increased cancer risk at levels above the MCL over long periods of exposure. If your levels are above 50 ppb for either, activated carbon filtration can significantly reduce them.

Priority 3: Nitrates

Nitrate MCL: 10 ppm. Critical for households with infants, as high nitrate levels can cause "blue baby syndrome" (methemoglobinemia). Common in agricultural areas.

Priority 4: PFAS (New in 2026)

The new EPA regulations require utilities to test and report PFAS levels starting in 2026. Look for PFOA, PFOS, and other PFAS compounds in your next CCR. MCLs are 4 ppt for PFOA and PFOS individually, with a hazard index approach for mixtures of other PFAS compounds.

Step 5: Compare Your Water Over Time

Save your CCR each year and compare results. Trends matter more than individual snapshots. A contaminant level that is rising steadily, even if it is still below the MCL, may indicate an emerging issue worth monitoring.

Questions to ask when reviewing trends:

Are any contaminant levels increasing year over year?

Have any new contaminants appeared that were not previously detected?

Has your utility changed its water source or treatment process?

Are disinfection byproducts higher in summer months? (This is common and often noted in the report.)

Step 6: Know When to Take Action

Your CCR gives you the information you need to make informed decisions. Here is a decision framework:

All contaminants well below MCLs, no violations: Your water meets all federal safety standards. No action is necessary unless you have taste or aesthetic preferences.

Contaminants at 50-100% of MCL: Technically in compliance, but some health-conscious homeowners choose to add point-of-use filtration as an extra precaution, especially for lead, PFAS, and disinfection byproducts.

Any MCL violation: Your utility is required to notify you and take corrective action. In the meantime, consider bottled water or certified filtration for the specific contaminant that was exceeded. Check our [water filter guide](/blog/should-you-buy-water-filter-data-driven-guide) for recommendations.

Special situations: If you are pregnant, have an infant, or have a compromised immune system, consider stricter personal standards than the MCLs provide. The MCLGs (goals) may be a better benchmark for vulnerable populations.

Beyond the CCR: Additional Testing

The CCR tells you about water quality at the treatment plant and in the distribution system, but it does not account for what happens between the water main and your faucet. Your home's plumbing — particularly if it includes lead pipes, lead solder, or brass fixtures — can add contaminants after the utility's testing points.

If your home was built before 1986, consider testing your tap water independently for lead. Home test kits are available for $20-50, and certified laboratory tests typically cost $20-40 for a lead-specific analysis. Visit our [DIY testing guide](/blog/diy-home-water-testing-vs-lab-tests) for step-by-step instructions.

Making the CCR Work for You

Your annual water quality report is one of the most transparent consumer documents produced by any industry. No other utility — gas, electric, or internet — gives you this level of detail about their product. Use it. Read it each year when it arrives, compare it to previous years, and let it inform your decisions about filtration, plumbing, and the safety of the water your family drinks every day.

For a quick overview of how your area's water quality compares to the rest of the country, search your state or city on our [rankings page](/rankings) or explore our [state-by-state data](/all-states).

This article is for informational purposes only. Consult your water utility or a water quality professional for questions about your specific water supply.